Upgrading from Vista to Windows 7

My wife has an Acer laptop with Vista which is fine for her needs, but on installing Malwarebytes I realised that the real time protection against ransomeware only worked on W7 and above. I have seen adverts to the effect that it can be upgraded to W7 without a clean install and not loosing or having to reinstall files etc. As we both have limited experience in these things I would appreciate advice on how easy or not this might be and things to watch out for. Thanks in anticipation.